Slashdot videos: Now with more Slashdot!

View

Discuss

Share

We've improved Slashdot's video section; now you can view our video interviews, product close-ups and site visits with all the usual Slashdot options to comment, share, etc. No more walled garden! It's a work in progress -- we hope you'll check it out (Learn more about the recent updates).

Scientists at the European Space Agency are using techniques inspired by their experience with outer space to make new and better products here on Earth. Certain compounds and alloys which are not normally viable can be made in different ways once forces such as gravity are removed from the equation. From BBC News:
"The near absence of gravity (microgravity) has a profound influence on the way molten metals come together to form intermetallics and 'standard' alloys. With no 'up' and 'down' in the space environment, a melt doesn't rise and sink as it would at the planet's surface and that means solidification can turn out very differently. 'Gravity induces a lot of segregation of the elements,' explains IMPRESS scientist Dr Guillaume Reinhart. 'For instance, tantalum and niobium are heavy atoms and in doing the solidification process on the ground, they will segregate in different places and produce a very heterogeneous material. If you do this in microgravity, you obtain a very homogenous material because you prevent separation; and you have a much more efficient material, mechanically.'"

Sure. But what if you keep rotating the mold as it cools down? Or do something similar?

But yeah, people often don't want a homogeneous material, they want stuff like the material being different at the edges from the core. So maybe "weightless" environments might help (lots more control), but without real numbers - significant difference in alloy strength or other characteristics, it's just not very exciting to me.

Actually, orbiting is considered free falling, and that can obviously last much longer than a few hours. That's one of the main reasons that newbie astronauts vomit in space, because even though it looks like they experience no sensation, they actually feel like they are falling 24/7 (an extremely nauseating event).

Ignoring the deceleration problem at the bottom, with a 5 km shaft (which is not cheap to make) you only get 30 seconds of free fall to work with. And that's in a vacuum! In any shaft on earth, you are going to have air, which means you will hit terminal velocity at some point, which will ruin the effect.

This duration of free fall is comparable to the Vomit Comet, which can produce brief periods of free fall without the ugly smashing part at the bottom of a mine shaft.:)

Terminal velocity can be overcome by generating a partial vacuum in the tower, and by accelerating the falling cabin downwards past terminal velocity, on some sort of rail system.

You don't need vacuum. Terminal velocity is based on the maximum speed of a falling object due to drag. If it's not falling, but instead being pushed, then it's not subject to terminal velocity, just loss of energy due to drag, like your car... until you drive off a cliff anyway.

you are off by a factor of 2.you are correct that a 5km drop gets you ~30 seconds of freefall (0.5at^2). but you could start at the bottom of the shaft and launch up (with a brief high-g acceleration) and then be in freefall all the way up and all the way down, for ~60 seconds of uninterupted freefall. The high-g at lauch would be the same as the breaking g at the end of the trip.you could get 30 seconds of freefall with only 1.125 km worth of shaft.just a nitpick, but...-Rob

You speak like a physicist, not an engineer. In theory, you are correct. In reality, how will you launch the material, such that it travels at exactly 0 degrees from vertical, at the required velocity? Solving for v in m*h*g=0.5*m*v^2 I get 150 m/s launch velocity. At perfect vertical. On a payload that contains a manufacturing process, probably including a molten metal. More than a kilometer below ground level.

In the drop facility Fallturm Bremen University of Bremen in Bremen, a catapult can be used to throw the experiment upwards to prolong the weightlessness from 4.74 to nearly 10 seconds. Neglecting the physical space needed for the initial acceleration, this technique doubles the effective period of weightlessness.

IIRC, lead shots were made by dropping molten lead down a tall chimney-like structure, they'd be cool enough to stay solid by the time they got to the bottom. Know how a raindrop is a sphere? Same principle.

This is exactly what we need to jump-start serious commercial investment from companies like Dow Chemicals in space exploration. They'll never give more than token amounts to a project which is for the "betterment of mankind and improvement of human knowledge".

But...if they think that they can make products superior to their competitors (or even better, products which are unique) then you can bet they'll be very interested in setting up orbital refineries and finding economical ways of doing it.

This is the first really hopeful news about a continued human presence in space that I've heard in quite some time (Virgin's space gimmicks notwithstanding).

I think that, in the minds of your average person, the "conquest of space" was completed back in the late 1960's and now most view it as a drain on the budget and a waste of resources better used elsewhere. Unfortunately this mindset is also present in the c-levels that make such policy decisions.

*sighs* Yet another case of chicken and the egg... If a company were to successfully profit from space, development in space, or research then most companies, such as your aforementioned Dow, would be all over t

Scientists at the European Space Agency are using techniques inspired by their experience with outer space.

And this is why companies should understand that science projects that are for the betterment of mankind and for the improvement of human knowledge are long term investments.

The problem is that the goal of corporations is to make a lot of profit in the short term. Rare are the corporations that are planning their growth in the long term. They plan for the coming years, not the coming 25 years.

After all, where could useless theoritical research from imbeciles that live in their heads like James Clerk M

Exactly. Pure science will always have its backers, but if you can convince politicians by connecting the dots between pure science and applied science you can convince a few more to lead. Stuff like this is only an earmark or two away from tenability.

Even if you can make a hypothesis that connects pure science to applied science ONLY IN THEORY, that can be the leash tug that results in real advancement.

I concur. It is about time private companies start picking up the slack that NASA has. I am sure there are ways that companies can make their own methods and techniques to explore space. This is in addition to the money that can be made by advancing science and technology.

What I feel is going on is that since there is no space race anymore, John and Susie Q Public have little interest in space anymore. Never mind the fact that one day we have to consider getting off of Earth. Space is a new frontier and

What about the expense? It's still insanely expensive to push pounds into space and bring them back. Until national governments absorb more of the R&D to get us to the point of cheap space travel, Corporate America will not follow. Spare me the Ron Paul rhetoric. If Dow saw profit in it, they would have done so by now. This is not news. We've known this for decades.

Sorry, I'm going to have to inject some Ron Paul rhetoric in here.National governments can't absorb the R&D for space missions when they're too busy spending all their money on foreign wars, and on keeping the oversized military stationed in well over 100 countries overseas. If we eliminated all that unnecessary expense, it'd probably be a lot easier to spend 1/10 of it on the space program, which would be a gigantic increase over its present budget.

Back when the Shuttle was called the "National Space Transportation System" and NASA was claiming that launch costs would come down, NASA used to talk about materials processing in space. That was a long time ago.

The trouble with materials processing in space is that for small things, gravity is dominated by surface tension and other forces like Brownian motion. So biological processing in space never amounted to much. Some early Shuttle flights carried an electrophoresis apparatus designed for zero-G operation to make some kind of diabetes drug. But bioengineering went beyond that approach; today it's easier to engineer some bacterium to crank out whatever you need.

For big objects, there would be some advantages (and many disadvantages) to working in zero G. Handling molten metal in zero G safely would be tough. One molten droplet could puncture anything we currently send into space. With gravity and in air, molten droplets
don't travel very far and cool. In space, they can go a long way.
Steel mills use floors of dirt or refractory brick in molten metal areas; concrete will blow up when its water content boils.
Welding in space [newscientist.com] has been tried, but on a very small scale, and very nervously.

Lift to orbit is far too expensive to justify flying heavy metal up there for casting and welding.
This is one of those ideas that won't be feasible unless and until lift to orbit costs about what long distance air travel costs now.

This is one of those ideas that won't be feasible unless and until lift to orbit costs about what long distance air travel costs now.

It's feasible if the new material is worth more then its production and transportation costs. There might be very valuable use-cases, so your statement seems a bit to early in my opinion. It might be worth it to check it out.

The problem with this is that asteroids are very spread apart in our solar system, moving quickly, and usually also far away. Just getting to asteroids with any sort of heavy equipment capable of processing and refining it into useful metal will require a ridiculous amount of fuel.Getting it back to earth also very tricky. The US has at great expense designed systems capable of bringing space shuttles and command modules safely from orbit to the ocean or ground. The problem is, these are all expensive an

I beg to disagree! The potential usefulness of novel vacuum cast alloys is incalculable. I just can't stand the attitude that we should not do a thing because of expense or difficulty. A REAL engineer rolls up his sleeves and figures it out! Who knows? Some material(s) yet to be invented, only possible to make in a vacuum may be the key to making a spacecraft efficient enough to bring down launch costs! Developing new technologies is always difficult and expensive, but you never learn how to do anything until you overcome the obstacles and DO it!!

I just can't stand the attitude that we should not do a thing because of expense or difficulty.

I can't stand the attitude that we should do something at ridiculous expense merely because we're too dumb to figure out if there's any payout to it or how we can do it for less. "Incalculable" doesn't mean that it'll have any value. As I see it, the only sane way to approach space development and exploration is to use those scarce resources in an effective manner. That means paying a lot of attention to expense and getting a good idea of possible payout. If we don't know enough then explore the space in

I would like to add to this: Sometimes you can already "learn" by making a careful analysis and perform a few preliminary test, find alternative ways and save a lot of money and time. As a scientist I sometimes talk to engineers who want to solve everything by "rolling up their sleeves" and DO: a gazillion of experiments just to avoid having to read the literature and look for causes of their problem. Because they end up thinking the cause is not their problem, their problem is their problem.

Everyone loves the overpowered monstrous Gundams, but there's something in me that likes the simpler Zakus. I also like the RK-92 Savage from Full Metal Panic. There's just something about clunky, mass-produced military technology.

Well... yes. But the context (even the article summary) gives us that answer.
The desired properties are heterogenity. By its nature a single crystal's elements are homogenously spread.

'For instance, tantalum and niobium are heavy atoms and in doing the solidification process on the ground, they will segregate in different places and produce a very heterogeneous material. If you do this in microgravity, you obtain a very homogenous material because you prevent separation; and you have a much more efficient material, mechanically.'

Yes, the summary did give that one property (homogeneity). Aren't there dozens of other properties that might be relevant in deciding whether or not the problem is 'solved', though? Certainly I couldn't take any old homogeneous substance and make an awesome turbofan blade out of it.

I guess what I'm saying is that the point of materials science research like this is often to discover new materials with new sets of properties. I don't think they're aiming right at exactly what single crystal superalloy tech can do already. I think they're asking "what cool materials can we make this way?"

I think I see your point - it might be just a semantic one, but an interesting point anyway.

True, the gravitation attraction of the earth still exists in orbit. In fact, it is what keeps the fast-moving ISS from flying off into space, because gravity keeps pulling the sideways-moving ISS down towards the Earth's center. This constant falling-but-never-landing state is called orbit.

But can anyone please explain how this gravitation system affects experiments onboard the ISS? Common sense seems to in

Orbit isn't the same as no gravity, but the difference is usually small enough to ignore. Any mass warps the spacetime around it, so there is a difference between orbit (freefall) and zero gravity (which is what you'd get a long, long way from anything). As one example, according to General Relativity, your proximity to a large mass affects the rate of the passage time. The clocks on GPS satellites are set to tick faster than ground-based clocks, so that when in orbit the clocks on the satellites appear to

I've always liked the idea of microgravity materials processes, but with launch costs the way they are, there isn't any way you're going to manufacture some novel material in space for use on the ground. There remains a lot of "interest" in microgravity processing in space, but largely it's because there's nothing else you can work on to justify having a space station.

One caveat that there might be some scientific value to cranking out samples in orbit (e.g. creating samples large enough to do x-ray crys